#heart:before,
#heart:after {
  position: absolute;
  left: 25px;
  top: 0;
  content: "";
  width: 25px;
  height: 40px;
  background: red;
  border-radius: 40px 40px 0 0;
  transform: rotate(-45deg);
  transform-origin: 0 100%;
}
#heart:after {
  content: "";
  left: 0;
  top: 0;
  transform: rotate(45deg);
  transform-origin: 100% 100%;
}

css 三角形
.icon-v-right {
    width: 20px;
    height: 20px;
    border: 5px solid blue;
    border-width: 5px 5px 0 0;
    transform: rotate(45deg);
}